Fixing build

[galloj]

Fixing the following build error:

clang++ -std=c++20 -O3 -flto -funroll-loops -fno-exceptions -DNDEBUG -Wall -Wextra -pthread -march=native -mtune=native -MMD -MP -c Board.cpp -o Board.o
In file included from Board.cpp:1:
In file included from ./Board.h:2:
In file included from ./Move.h:2:
./Utils.h:304:6: error: no template named 'optional' in namespace 'std'
std::optional<bool> ParseUCIBoolean(const std::string_view str);
~~~~~^
1 error generated.
make: *** [makefile:82: Board.o] Error 1

[pkrisz99]

Thank you for spotting! Was it on g++ or another compiler?

[galloj]

It was clang++. Just a default setup, it is kinda weird that the build was working for you and failed for me. Maybe a different version of the compiler? My is 14.0.0-1ubuntu1.1.